[gdal-dev] Extracting data from a parquet file

[Even Rouault]

Joaquim,

The GeoPackage format only supports one geometry field per layer. and 
the QGIS OGR provider doesn't know currently how to handle several 
geometry fields per layer too

To do what you want, you need to explictly select the desired geometry 
field name with:

ogr2ogr out.gpkg world-administrative-boundaries.parquet -sql "select 
geo_shape, * from \"world-administrative-boundaries\""

Actually if you outputted to a format that supports several geometry 
fields per layer (let's say PostGIS), the above wouldn't work. You would 
need to exclude the geometry fields from the wildcard * selection with:

ogr2ogr out.gpkg  world-administrative-boundaries.parquet -sql "select 
geo_shape, * exclude (geo_point_2D, geo_shape) from 
\"world-administrative-boundaries\""

Even

Le 19/07/2024 à 16:58, Joaquim Manuel Freire Luís via gdal-dev a écrit :
>
> Hi,
>
> I finally managed to build a working GDAL with the arrow/parquet 
> driver and I’m now trying to convert this file
>
> (https://public.opendatasoft.com/api/explore/v2.1/catalog/datasets/world-administrative-boundaries/exports/parquet?lang=en&timezone=Europe%2FLondon 
> <https://public.opendatasoft.com/api/explore/v2.1/catalog/datasets/world-administrative-boundaries/exports/parquet?lang=en&timezone=Europe%2FLondon>)
>
> but can only extract the “Point”, not the “Multi polygon”
>
> ogrinfo world-administrative-boundaries.parquet
>
> INFO: Open of `world-administrative-boundaries.parquet'
>
>       using driver `Parquet' successful.
>
> 1: world-administrative-boundaries (Point, Multi Polygon)
>
> This gets only the points
>
> ogr2ogr lixo.gpkg world-administrative-boundaries.parquet
>
> The same happens if I open the file in QGis. Points only, no polygons.
>
> But if I do an ogrinfo -al, it prints all data in file.
>
> ogrinfo -al world-administrative-boundaries.parquet
>
> ….
>
> OGRFeature(world-administrative-boundaries):255
>
>   iso3 (String) = GIB
>
>   status (String) = UK Non-Self-Governing Territory
>
>   color_code (String) = GBR
>
>   name (String) = Gibraltar
>
> …
>
> So, how can we select in ogr2ogr to extract the polygons?
>
>
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